In the recent past, investigations concerned with mammalian nervous systems have been very informative. Establishment of the normal functioning of chemical transmitters has provided essential background material. Two neurotransmitter systems, the catecholamines and indoleamines, appear to be intimately connected to emotional behavior. Thus, the investigation of these compounds, and enzymes involved in their biosynthesis, in studies related to mental disorders is a quite natural endeavor. The present proposal intends to extend the existing methodology by producing more sensitive and broadly applicable techniques. By utilizing liquid chromatography combined with electrochemical detection, the sensitivity of common analyses will be lowered by a projected factor of 1000. The developed methods for endogenous components and relevant enzymatic systems will simultaneously be capable of detecting extremely small quantities of possible neurotoxins. These agents have been mentioned as a possible etiology of mental diseases. The proposal offers the first substantial attempt to identify such destructive molecules. The enzymatic systems will also be examined for possible abnormal products.